| Message ID | 1467291379.11238.8.camel@edumazet-glaptop3.roam.corp.google.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
On Thu, Jun 30, 2016 at 2:56 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > From: Eric Dumazet <edumazet@google.com> > > ether_addr_equal_64bits() requires some care about its arguments, > namely that 8 bytes might be read, even if last 2 byte values are not > used. > > KASan detected a violation with null_mac_addr and lacpdu_mcast_addr > in bond_3ad.c > > Fixes: 815117adaf5b ("bonding: use ether_addr_equal_unaligned for bond addr compare") > Fixes: bb54e58929f3 ("bonding: Verify RX LACPDU has proper dest mac-addr") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: Dmitry Vyukov <dvyukov@google.com> > --- > drivers/net/bonding/bond_3ad.c | 11 +++++++---- > drivers/net/bonding/bond_alb.c | 3 --- > include/net/bonding.h | 7 ++++++- > 3 files changed, 13 insertions(+), 8 deletions(-) > > diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c > index ca81f46ea1aa..8ad491ab1d01 100644 > --- a/drivers/net/bonding/bond_3ad.c > +++ b/drivers/net/bonding/bond_3ad.c > @@ -101,11 +101,14 @@ enum ad_link_speed_type { > #define MAC_ADDRESS_EQUAL(A, B) \ > ether_addr_equal_64bits((const u8 *)A, (const u8 *)B) > > -static struct mac_addr null_mac_addr = { { 0, 0, 0, 0, 0, 0 } }; > +static const u8 null_mac_addr[ETH_ALEN] __long_aligned = { > + 0, 0, 0, 0, 0, 0 > +}; __long_aligned won't prevent KASAN from barking, it's still 6 bytes but we are reading 8. Can we please do "ETH_ALEN + 2" as below? > static u16 ad_ticks_per_sec; > static const int ad_delta_in_ticks = (AD_TIMER_INTERVAL * HZ) / 1000; > > -static const u8 lacpdu_mcast_addr[ETH_ALEN] = MULTICAST_LACPDU_ADDR; > +static const u8 lacpdu_mcast_addr[ETH_ALEN] __long_aligned = > + MULTICAST_LACPDU_ADDR; > > /* ================= main 802.3ad protocol functions ================== */ > static int ad_lacpdu_send(struct port *port); > @@ -1739,7 +1742,7 @@ static void ad_clear_agg(struct aggregator *aggregator) > aggregator->is_individual = false; > aggregator->actor_admin_aggregator_key = 0; > aggregator->actor_oper_aggregator_key = 0; > - aggregator->partner_system = null_mac_addr; > + eth_zero_addr(aggregator->partner_system.mac_addr_value); > aggregator->partner_system_priority = 0; > aggregator->partner_oper_aggregator_key = 0; > aggregator->receive_state = 0; > @@ -1761,7 +1764,7 @@ static void ad_initialize_agg(struct aggregator *aggregator) > if (aggregator) { > ad_clear_agg(aggregator); > > - aggregator->aggregator_mac_address = null_mac_addr; > + eth_zero_addr(aggregator->aggregator_mac_address.mac_addr_value); > aggregator->aggregator_identifier = 0; > aggregator->slave = NULL; > } > diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c > index c5ac160a8ae9..26beed070bf0 100644 > --- a/drivers/net/bonding/bond_alb.c > +++ b/drivers/net/bonding/bond_alb.c > @@ -42,9 +42,6 @@ > > > > -#ifndef __long_aligned > -#define __long_aligned __attribute__((aligned((sizeof(long))))) > -#endif > static const u8 mac_bcast[ETH_ALEN] __long_aligned = { > 0xff, 0xff, 0xff, 0xff, 0xff, 0xff > }; > diff --git a/include/net/bonding.h b/include/net/bonding.h > index 791800ddd6d9..6360c259da6d 100644 > --- a/include/net/bonding.h > +++ b/include/net/bonding.h > @@ -34,6 +34,9 @@ > > #define BOND_DEFAULT_MIIMON 100 > > +#ifndef __long_aligned > +#define __long_aligned __attribute__((aligned((sizeof(long))))) > +#endif > /* > * Less bad way to call ioctl from within the kernel; this needs to be > * done some other way to get the call out of interrupt context. > @@ -138,7 +141,9 @@ struct bond_params { > struct reciprocal_value reciprocal_packets_per_slave; > u16 ad_actor_sys_prio; > u16 ad_user_port_key; > - u8 ad_actor_system[ETH_ALEN]; > + > + /* 2 bytes of padding : see ether_addr_equal_64bits() */ > + u8 ad_actor_system[ETH_ALEN + 2]; > }; > > struct bond_parm_tbl { > >
On 30/06/16 14:56, Eric Dumazet wrote: > From: Eric Dumazet <edumazet@google.com> > > ether_addr_equal_64bits() requires some care about its arguments, > namely that 8 bytes might be read, even if last 2 byte values are not > used. > > KASan detected a violation with null_mac_addr and lacpdu_mcast_addr > in bond_3ad.c > > Fixes: 815117adaf5b ("bonding: use ether_addr_equal_unaligned for bond addr compare") > Fixes: bb54e58929f3 ("bonding: Verify RX LACPDU has proper dest mac-addr") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: Dmitry Vyukov <dvyukov@google.com> > --- > drivers/net/bonding/bond_3ad.c | 11 +++++++---- > drivers/net/bonding/bond_alb.c | 3 --- > include/net/bonding.h | 7 ++++++- > 3 files changed, 13 insertions(+), 8 deletions(-) > Good catch, Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
On Thu, 2016-06-30 at 15:04 +0200, Dmitry Vyukov wrote: > On Thu, Jun 30, 2016 at 2:56 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > > From: Eric Dumazet <edumazet@google.com> > > > > ether_addr_equal_64bits() requires some care about its arguments, > > namely that 8 bytes might be read, even if last 2 byte values are not > > used. > > > > KASan detected a violation with null_mac_addr and lacpdu_mcast_addr > > in bond_3ad.c > > > > Fixes: 815117adaf5b ("bonding: use ether_addr_equal_unaligned for bond addr compare") > > Fixes: bb54e58929f3 ("bonding: Verify RX LACPDU has proper dest mac-addr") > > Signed-off-by: Eric Dumazet <edumazet@google.com> > > Reported-by: Dmitry Vyukov <dvyukov@google.com> > > --- > > drivers/net/bonding/bond_3ad.c | 11 +++++++---- > > drivers/net/bonding/bond_alb.c | 3 --- > > include/net/bonding.h | 7 ++++++- > > 3 files changed, 13 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c > > index ca81f46ea1aa..8ad491ab1d01 100644 > > --- a/drivers/net/bonding/bond_3ad.c > > +++ b/drivers/net/bonding/bond_3ad.c > > @@ -101,11 +101,14 @@ enum ad_link_speed_type { > > #define MAC_ADDRESS_EQUAL(A, B) \ > > ether_addr_equal_64bits((const u8 *)A, (const u8 *)B) > > > > -static struct mac_addr null_mac_addr = { { 0, 0, 0, 0, 0, 0 } }; > > +static const u8 null_mac_addr[ETH_ALEN] __long_aligned = { > > + 0, 0, 0, 0, 0, 0 > > +}; > > __long_aligned won't prevent KASAN from barking, it's still 6 bytes > but we are reading 8. > Can we please do "ETH_ALEN + 2" as below? Really ? sizeof(null_mac_addr) is 8, how KASan would decide it is 6 bytes ? nm -v drivers/net/bonding/bonding.ko|grep -3 null_mac_addr 000000000000084a r __UNIQUE_ID_mode17 0000000000000850 r tmpl.46263 0000000000000860 r lacpdu_mcast_addr 0000000000000868 r null_mac_addr 0000000000000870 r mac_v6_allmcast 0000000000000878 r mac_bcast 0000000000000880 r slave_sysfs_ops Same trick was used in https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=885a136c52a8871175477baf3903e1c38751b35a
On Thu, Jun 30, 2016 at 3:25 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > On Thu, 2016-06-30 at 15:04 +0200, Dmitry Vyukov wrote: >> On Thu, Jun 30, 2016 at 2:56 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: >> > From: Eric Dumazet <edumazet@google.com> >> > >> > ether_addr_equal_64bits() requires some care about its arguments, >> > namely that 8 bytes might be read, even if last 2 byte values are not >> > used. >> > >> > KASan detected a violation with null_mac_addr and lacpdu_mcast_addr >> > in bond_3ad.c >> > >> > Fixes: 815117adaf5b ("bonding: use ether_addr_equal_unaligned for bond addr compare") >> > Fixes: bb54e58929f3 ("bonding: Verify RX LACPDU has proper dest mac-addr") >> > Signed-off-by: Eric Dumazet <edumazet@google.com> >> > Reported-by: Dmitry Vyukov <dvyukov@google.com> >> > --- >> > drivers/net/bonding/bond_3ad.c | 11 +++++++---- >> > drivers/net/bonding/bond_alb.c | 3 --- >> > include/net/bonding.h | 7 ++++++- >> > 3 files changed, 13 insertions(+), 8 deletions(-) >> > >> > diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c >> > index ca81f46ea1aa..8ad491ab1d01 100644 >> > --- a/drivers/net/bonding/bond_3ad.c >> > +++ b/drivers/net/bonding/bond_3ad.c >> > @@ -101,11 +101,14 @@ enum ad_link_speed_type { >> > #define MAC_ADDRESS_EQUAL(A, B) \ >> > ether_addr_equal_64bits((const u8 *)A, (const u8 *)B) >> > >> > -static struct mac_addr null_mac_addr = { { 0, 0, 0, 0, 0, 0 } }; >> > +static const u8 null_mac_addr[ETH_ALEN] __long_aligned = { >> > + 0, 0, 0, 0, 0, 0 >> > +}; >> >> __long_aligned won't prevent KASAN from barking, it's still 6 bytes >> but we are reading 8. >> Can we please do "ETH_ALEN + 2" as below? > > Really ? > > sizeof(null_mac_addr) is 8, how KASan would decide it is 6 bytes ? > > nm -v drivers/net/bonding/bonding.ko|grep -3 null_mac_addr > > 000000000000084a r __UNIQUE_ID_mode17 > 0000000000000850 r tmpl.46263 > 0000000000000860 r lacpdu_mcast_addr > 0000000000000868 r null_mac_addr > 0000000000000870 r mac_v6_allmcast > 0000000000000878 r mac_bcast > 0000000000000880 r slave_sysfs_ops What does nm -S say? I've tried to compile a sample program with gcc6 and __attribute__((aligned(8))) does in fact force alignment of start of the symbol, but size still stays 6. (and asan still barks on my test program).
On Thu, 2016-06-30 at 15:35 +0200, Dmitry Vyukov wrote: > > What does nm -S say? > I've tried to compile a sample program with gcc6 and > __attribute__((aligned(8))) does in fact force alignment of start of > the symbol, but size still stays 6. (and asan still barks on my test > program). Right, but then it means I also need to change mac_bcast[] and mac_v6_allmcast[] in bond_alb.c to avoid false positive. (Technically, if their alignment is 8, we have 8 bytes there, no way it could span 2 pages) I'll send a v2.
On Thu, Jun 30, 2016 at 4:08 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > On Thu, 2016-06-30 at 15:35 +0200, Dmitry Vyukov wrote: > >> >> What does nm -S say? >> I've tried to compile a sample program with gcc6 and >> __attribute__((aligned(8))) does in fact force alignment of start of >> the symbol, but size still stays 6. (and asan still barks on my test >> program). > > Right, but then it means I also need to change mac_bcast[] and > mac_v6_allmcast[] in bond_alb.c to avoid false positive. > > (Technically, if their alignment is 8, we have 8 bytes there, > no way it could span 2 pages) Agree. > I'll send a v2. Thanks!
diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c index ca81f46ea1aa..8ad491ab1d01 100644 --- a/drivers/net/bonding/bond_3ad.c +++ b/drivers/net/bonding/bond_3ad.c @@ -101,11 +101,14 @@ enum ad_link_speed_type { #define MAC_ADDRESS_EQUAL(A, B) \ ether_addr_equal_64bits((const u8 *)A, (const u8 *)B) -static struct mac_addr null_mac_addr = { { 0, 0, 0, 0, 0, 0 } }; +static const u8 null_mac_addr[ETH_ALEN] __long_aligned = { + 0, 0, 0, 0, 0, 0 +}; static u16 ad_ticks_per_sec; static const int ad_delta_in_ticks = (AD_TIMER_INTERVAL * HZ) / 1000; -static const u8 lacpdu_mcast_addr[ETH_ALEN] = MULTICAST_LACPDU_ADDR; +static const u8 lacpdu_mcast_addr[ETH_ALEN] __long_aligned = + MULTICAST_LACPDU_ADDR; /* ================= main 802.3ad protocol functions ================== */ static int ad_lacpdu_send(struct port *port); @@ -1739,7 +1742,7 @@ static void ad_clear_agg(struct aggregator *aggregator) aggregator->is_individual = false; aggregator->actor_admin_aggregator_key = 0; aggregator->actor_oper_aggregator_key = 0; - aggregator->partner_system = null_mac_addr; + eth_zero_addr(aggregator->partner_system.mac_addr_value); aggregator->partner_system_priority = 0; aggregator->partner_oper_aggregator_key = 0; aggregator->receive_state = 0; @@ -1761,7 +1764,7 @@ static void ad_initialize_agg(struct aggregator *aggregator) if (aggregator) { ad_clear_agg(aggregator); - aggregator->aggregator_mac_address = null_mac_addr; + eth_zero_addr(aggregator->aggregator_mac_address.mac_addr_value); aggregator->aggregator_identifier = 0; aggregator->slave = NULL; } diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c index c5ac160a8ae9..26beed070bf0 100644 --- a/drivers/net/bonding/bond_alb.c +++ b/drivers/net/bonding/bond_alb.c @@ -42,9 +42,6 @@ -#ifndef __long_aligned -#define __long_aligned __attribute__((aligned((sizeof(long))))) -#endif static const u8 mac_bcast[ETH_ALEN] __long_aligned = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; diff --git a/include/net/bonding.h b/include/net/bonding.h index 791800ddd6d9..6360c259da6d 100644 --- a/include/net/bonding.h +++ b/include/net/bonding.h @@ -34,6 +34,9 @@ #define BOND_DEFAULT_MIIMON 100 +#ifndef __long_aligned +#define __long_aligned __attribute__((aligned((sizeof(long))))) +#endif /* * Less bad way to call ioctl from within the kernel; this needs to be * done some other way to get the call out of interrupt context. @@ -138,7 +141,9 @@ struct bond_params { struct reciprocal_value reciprocal_packets_per_slave; u16 ad_actor_sys_prio; u16 ad_user_port_key; - u8 ad_actor_system[ETH_ALEN]; + + /* 2 bytes of padding : see ether_addr_equal_64bits() */ + u8 ad_actor_system[ETH_ALEN + 2]; }; struct bond_parm_tbl {